Here We Go Again..

[Kane 34]

Some of you might be aware of the saga I've had with my mi16 rebuild and I'd like to say that I've sussed it all out but unfortunately I'm not so lucky.

 

During the running in period of the engine it was apparent that there was an issue with the top end. I could hear a constant 'tap tap tap' noise which i suspected was a failed hydraulic lifter. So off with the head and a full top end strip down was carried out. I thought since i had it off I'd send it off to be checked over and it turned out all of the exhaust guides were out of spec, more money down the pan.

 

I've only recently managed to have a few hours to put the engine back together and would you guess it upon starting it up the tapping noise is still there. Following the previous discovery of the bent valves i put the tapping down to this although i did inspect all the buckets while it was apart. All barring one bucket was still primed with oil so i stripped apart the individual bucket assuming to find a collapsed spring or something but everything was perfectly intact. I probably should have sourced a replacement but didn't think it necessary since there wasn't any sign of damage to the internals of the lifter.

 

Could the lifter become damaged so that it will never be able to prime and as a result not offer the required resistance against the cam lobe ultimately leading to this tap tap tap issue?

 

Alternatively i have read that flat spots on the nose of the cam can result in the issue, has anyone experienced this previously and is it common with standard xu9j4 cams?

 

On a side note, upon starting up the engine i have seen a reasonable amount of white smoke rising from the manifold-downpipe join. It looks to be coming from inside the exhaust and not due to oil dripping onto the manifold and burning off. I only had the car running for a matter of about 5 minutes so assume this may be a combination of condensation and liquid gasket burning off although what other possibilities should i look out to be the cause of this?

 

Could it be poor liner sealing? For info, the block and liners were machined to suit when the works was carried out and as far as i can remember the oil changes during the running in period did not appear to show a 'milky' appearance. Liner protrusion was also checked during initial rebuild and were ok as far as i can recall.

 

I'm currently awaiting my new house being finished which I'll get the car moved into the garage in the new year so will inspect everything then but thought I'd throw up a few questions to hear your thoughts.

 

The first attempt of a rebuild was flawed due to a lack of patience, research and available time to have it completed. This time round however everything will be carried out with meticulous attention to detail to ensure that sometime in the near future (i hope sooner rather than later) that I'll have a car which is not only road worthy but is also something i can be proud to say I've built.

 

Any suggestions to help the situation are much appreciated.

 

Kane

[johniban 59 1 Cars]

Was it a loud tapping rather than a loud ticking? as ive seen engines before with a noisey injector

[Kane 34]

Possibly could have been a loud tap but I'm not exactly sure the difference. I didn't have the injectors serviced before building it back up so it is a possibility. In your experience would a good clean/service sort it out or would it be a replacement job?

 

I'll add it to my list of things to check once i get back on the car though. Thanks for the tip

[JeffR 51]

My experience with these engines is that it takes about 20 mins for the hydraulic lifters to fully prime and become quiet. If, as you say it's only ran it for 5 mins I'd restart and either let it idle for 20 mins until the thermo fans kick in with the occasional rev to help prime them.

 

Did you reface them as suggested on PeterT's website? I had a faily noisy set and after the reface engine was quiet again.

[boldy205 75]

I've had a lifter not primeven, wouldn't prime when idling, took it for a steady drive and after 5 mins it filled up. Maybe the oil being slightly warmer and therefore thinner helped.

[Kane 34]

I put about 1000 miles on the engine after it was initially rebuilt and the noise failed to go away then which is what prompted the second tear down. It was discovered at that time that there were 2 valves slightly out of shape (which i presumed was the cause of the noise) so these were replaced with more work being carried out on the seats to ensure a decent seal.

 

Since its been put back together following the second round of work i have only run it for a matter of minutes although i did pre-prime the lifters following the refurb as per PeterT's website so would have thought they wouldn't need time to fill back up. Could it be a case that I've over-filled them and this could be the source of the problem? I seem to recall reading on here of others having issues with over-filling and in the end they emptied all lifters of oil and let it rattle away for a while until they self-primed.

 

What are the typical failure mechanisms of this type of lifter? Is it usually just a case of the piston seizing in the bore?